/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __THP_SETTINGS_H__
#define __THP_SETTINGS_H__

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

enum thp_enabled {
        THP_NEVER,
        THP_ALWAYS,
        THP_INHERIT,
        THP_MADVISE,
};

enum thp_defrag {
        THP_DEFRAG_ALWAYS,
        THP_DEFRAG_DEFER,
        THP_DEFRAG_DEFER_MADVISE,
        THP_DEFRAG_MADVISE,
        THP_DEFRAG_NEVER,
};

enum shmem_enabled {
        SHMEM_NEVER,
        SHMEM_ALWAYS,
        SHMEM_WITHIN_SIZE,
        SHMEM_ADVISE,
        SHMEM_INHERIT,
        SHMEM_DENY,
        SHMEM_FORCE,
};

#define NR_ORDERS 20

struct hugepages_settings {
        enum thp_enabled enabled;
};

struct khugepaged_settings {
        bool defrag;
        unsigned int alloc_sleep_millisecs;
        unsigned int scan_sleep_millisecs;
        unsigned int max_ptes_none;
        unsigned int max_ptes_swap;
        unsigned int max_ptes_shared;
        unsigned long pages_to_scan;
};

struct shmem_hugepages_settings {
        enum shmem_enabled enabled;
};

struct thp_settings {
        enum thp_enabled thp_enabled;
        enum thp_defrag thp_defrag;
        enum shmem_enabled shmem_enabled;
        bool use_zero_page;
        struct khugepaged_settings khugepaged;
        unsigned long read_ahead_kb;
        struct hugepages_settings hugepages[NR_ORDERS];
        struct shmem_hugepages_settings shmem_hugepages[NR_ORDERS];
};

int read_file(const char *path, char *buf, size_t buflen);
int write_file(const char *path, const char *buf, size_t buflen);
unsigned long read_num(const char *path);
void write_num(const char *path, unsigned long num);

int thp_read_string(const char *name, const char * const strings[]);
void thp_write_string(const char *name, const char *val);
unsigned long thp_read_num(const char *name);
void thp_write_num(const char *name, unsigned long num);

void thp_write_settings(struct thp_settings *settings);
void thp_read_settings(struct thp_settings *settings);
struct thp_settings *thp_current_settings(void);
void thp_push_settings(struct thp_settings *settings);
void thp_pop_settings(void);
void thp_restore_settings(void);
void thp_save_settings(void);

void thp_set_read_ahead_path(char *path);
unsigned long thp_supported_orders(void);
unsigned long thp_shmem_supported_orders(void);

bool thp_available(void);
bool thp_is_enabled(void);

#endif /* __THP_SETTINGS_H__ */